/*
 * Copyright  2000-2004 The Apache Software Foundation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); 
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License. 
 *
 */
package org.apache.bcel.generic;

import org.apache.bcel.Constants;

/**
 * Super class for the x2y family of instructions.
 *
 * @version $Id: ConversionInstruction.java,v 1.1 2007/06/04 00:00:46 liqiang2000 Exp $
 * @author  <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
 */
public abstract class ConversionInstruction extends Instruction implements TypedInstruction,
        StackProducer, StackConsumer {

    /**
     * Empty constructor needed for the Class.newInstance() statement in
     * Instruction.readInstruction(). Not to be used otherwise.
     */
    ConversionInstruction() {
    }


    /**
     * @param opcode opcode of instruction
     */
    protected ConversionInstruction(short opcode) {
        super(opcode, (short) 1);
    }


    /** @return type associated with the instruction
     */
    public Type getType( ConstantPoolGen cp ) {
        switch (opcode) {
            case Constants.D2I:
            case Constants.F2I:
            case Constants.L2I:
                return Type.INT;
            case Constants.D2F:
            case Constants.I2F:
            case Constants.L2F:
                return Type.FLOAT;
            case Constants.D2L:
            case Constants.F2L:
            case Constants.I2L:
                return Type.LONG;
            case Constants.F2D:
            case Constants.I2D:
            case Constants.L2D:
                return Type.DOUBLE;
            case Constants.I2B:
                return Type.BYTE;
            case Constants.I2C:
                return Type.CHAR;
            case Constants.I2S:
                return Type.SHORT;
            default: // Never reached
                throw new ClassGenException("Unknown type " + opcode);
        }
    }
}
